Can I use gt1030 for rendering while useing igpu for my vga display?
Yes of course it's possible.
Blender used openGL. It's very old API and utilizing different GPU on it is hard. So most of the time blender use single GPU for normal usage. Note, if you useing motherboard's VGA port to open blender. It want to use iGPU instead of discrete GPU. As I am using windows, the OS smartly want to use the powerful graphic-card. Because powerful one is better then.
This two different requirements makes blender to crush before opening. This can be solved by silencing Windows's smartness.
To do that :---   Open setting in windows 10 -&gt; Search Graphics Setting -&gt; Open it -&gt; Below the classic app click on browse -&gt; Find and select Blender.exe (executable) -&gt; Click OK/Open -&gt; Then on Graphics Setting goto blender -&gt; options -&gt; set Power saving ( for motherboard's display connection) else automatic -&gt; Save it -&gt; Reboot and Check.
This solved my problem. But this tweak is OS specific. What about linux / MacOS? Question remains and testing needed. This problem should be solved on blender or openGL level.
Any suggestions or improvements is welcome.